An explosion hit a minibus unloading passengers in the capital of Russia's North Ossetia province on Thursday, killing 11 people, federal investigators said.

A duty officer at the Emergency Ministry in North Ossetia, who was not authorized to give his name, said the blast was caused by an improvised roadside bomb.

Passengers were getting off the bus near the entrance to the central market in Vladikavkaz, Russia's Investigative Committee said on its Web site.

The committee said it had opened an investigation into what may have been a terrorist attack. It said 11 people were killed.

North Ossetia borders war-scarred Chechnya as well as Georgia's breakaway South Ossetia region, the focus of a war in August between Russia and Georgia.

It has been the site of several bomb blasts since the start of Russia's wars against Chechen separatists over a decade ago.